Hitherto, offensive smells industrially emitted in factories and the like and offensive smells derived from wastes in service industries such as restaurants and hotels have been considered to be problematic. Recently, bad smells in spaces of daily life such as in automobiles and in common rooms have come under closer scrutiny.
Therefore, there are increasing needs for removal of harmful substances such as these smells, and hence air cleaners integrated with a deodorizing apparatus or a deodorizing filter have been actively developed.
On the other hand, in consideration of the global environment, reduction in weight of wastes is desired and it becomes a problem that the deodorizing filter turns into waste after use. Thus, it is required to use the deodorant filter repeatedly by regeneration.
Some of recent home electric appliances such as air conditioners have adopted a mode of regenerating their deodorizing ability by cleaning a filter with water or a detergent after using (for example, see JP-2002-066223 and JP-2001-070418). However, it is necessary for a user to remove and wash the filter regularly, and therefore, a more convenient regeneration method is desired.
In recent air cleaners, filters containing active carbon are employed and a method of removing harmful substances such as offensive smells by adsorbing thereof on the active carbon is adopted.
Among all, a deodorizing filter in which particulate active carbon is packed into cells of a honeycomb and both openings of the honeycomb are sealed with a gas-permeable base material has a large amount of active carbon per a unit volume and exhibits a high gas-permeability taking the amount of active carbon into consideration. Thus, it is especially excellent as a deodorizing filter using active carbon and hence is employed in various air cleaners.
Among recent air cleaning equipments, an equipment mounted with a deodorizing filter which is packed with active carbon capable of regeneration by washing with water has been commercially available, but the washing operation is difficult. Further, in general, the washing with water can regenerate the filter when hot water is used, but complete regeneration effect cannot be obtained when low-temperature water like tap water is used. In addition, since the particulate active carbon is not easily dried after washing, more convenient and effective regeneration method is desired.
Recently, there has been a raw garbage disposer in which a plate-form heater is provided in close contact with a honeycomb surface of a catalyst to impart a mechanism of thermal regeneration at 200° C. to 300° C. when the catalyst reaches saturation for adsorption of odors and oxidative decomposition and its deodorizing ability decreases.
However, in general air conditioning equipments, continuous use is problematic since it is a rare case where a heat source capable of achieving such a high temperature of 200° C. or higher is available and, in the case of using a catalyst, regeneration efficiency by thermal treatment is remarkably lowered when the catalyst surface is covered with dirt, dust, and the like and hence the catalyst becomes physically impossible to work (cf. JP-A-7-136628).
As the other equipment, there is reported a deodorizing equipment in which regeneration of deodorization performance is intended by heating an absorbent through electrification of the adsorbent as a heating means of odor components. However, the deodorant should be an electroconductive substance or a material having no conductivity should be subjected to a treatment for suitable impartment of conductivity. In addition, even when the adsorbent is electrified, it is virtually difficult to achieve uniform electrification of all over the adsorbent of the whole filter to reach a constant elevated temperature, so that the equipment is not suitable for practical use (cf. JP-B-7-16579).
Furthermore, as a deodorizing filter for an air cleaner, there is known a filter in which a deodorizing filter made of a non-woven fabric formed with a carbon fiber and capable of effecting deodorization by the reaction of the carbon fiber with odor components in the air and of releasing the adsorbed odor components by heating at about 110° C. is shaped into a flat pouch and a plate-form heater having air permeability is enveloped in the pouch-like deodorizing filter to integrated them, but the filter has a problem in view of regeneration efficiency (cf. JP-A-10-332).
An object (purpose) of the invention relates to a deodorizing filter having a large capacity of deodorization performance and is to provide a thermally regenerative deodorizing filter which can be repeatedly used by conducting a thermal regeneration treatment.